Online Etymology Dictionary

gallop (n.): "a leaping gait," the most rapid movement of a horse, 1520s, from gallop (v.).
gallow: singular of gallows.
Galloway: district in southwestern Scotland (Medieval Latin Gallovidia), equivalent to Welsh Gallwyddel, Irish Gallgaidhil, literally "foreign Gaels," containing the Gal- element also common in Irish place-names (Irish Gaelic gall) and meaning there "a stranger, a foreigner," especially an Englishman. Related: Gallovidian, which is from the Latin form of the name. The adjective Galwegian is on analogy of Norwegian.
gallows (n.): c. 1300, plural of Middle English galwe "gallows" (mid-13c.), from Old Norse galgi "gallows," or from Old English galga (Mercian), gealga (West Saxon) "gallows;" all from Proto-Germanic *galgon "pole" (source also of Old Frisian galga, Old Saxon galgo, Middle High German galge "gallows, cross," German Galgen "gallows," Gothic galga "cross"), from PIE *ghalgh- "branch, rod" (source also of Lithuanian zalga "pole, perch," Armenian dzalk "pole"). In Old English, also used of the cross of the crucifixion. Plural because made of two poles. Gallows-tree is Old English galg-treow. Gallows humor (1881) translates German Galgenhumor.
gallstone (n.): 1758, from gall (n.1) + stone (n.).
Gallup poll: 1940, from George H. Gallup (1901-1984), U.S. journalist and statistician, who in 1935 set up the American Institute of Public Opinion.
galoot (n.): 1812, nautical, "raw recruit, green hand," apparently originally a sailor's contemptuous word for soldiers or marines, of unknown origin. "Dictionary of American Slang" proposes galut, Sierra Leone creole form of Spanish galeoto "galley slave." In general (non-nautical) use by 1866, "awkward or boorish man," but often a term of humorous contempt.
galore (adv.): 1670s, from Irish go leór, and equivalent Scottish Gaelic gu leóir "sufficiently, enough," from Old Irish roar "enough," from Proto-Celtic *ro-wero- "sufficiency." The particle go/gu usually means "to," but it also is affixed to adjectives to form adverbs, as here. Often used in English with the force of a predicate adjective.
galosh (n.): see galoshes.
galoshes (n.): mid-14c. (surname Galocher is attested from c. 1300), "kind of footwear consisting of a wooden sole fastened onto the foot with leather thongs," perhaps from Old French galoche "overshoe, galosh" (singular), 13c., from Late Latin gallicula, diminutive of gallica (solea) "a Gallic (sandal)" [Klein]. Alternative etymology [Barnhart, Hatz.-Darm.] is from Vulgar Latin *galopia, from Greek kalopodion, diminutive of kalopous "shoemaker's last," from kalon "wood" (properly "firewood") + pous "foot" (see foot (n.)). "The name seems to have been variously applied" [OED]. Modern meaning "rubber covering of a boot or shoe" is from 1853.
galumph (v.): 1872, "to prance about in a self-satisfied manner," coined by Lewis Carroll in "Jabberwocky," apparently by blending gallop and triumph. "The sense in current use may vary according to different notions of what the sound expresses" [OED]. Related: Galumphing.
galvanic (adj.): 1797; see galvanism + -ic. Perhaps from or based on French galvanique. Related: Galvanical.
galvanise (v.): chiefly British English spelling of galvanize; for suffix, see -ize. Related: Galvanised; galvanising.
galvanism (n.): "electricity produced by chemical action," 1797, from French galvanisme or Italian galvanismo, from Luigi Galvani (1737-1798), professor of anatomy at Bologna, who discovered it c. 1792 while running currents through the legs of dead frogs.
galvanization (n.): 1798, formed as a noun of state to go with the vocabulary of galvanism; perhaps immediately from French galvanisation (1797 in the "Annales de chimie et de physique").
galvanize (v.): 1801, "stimulate by galvanic electricity," from French galvaniser, from galvanisme (see galvanism). Figurative sense of "excite, stimulate (as if by electricity)" first recorded 1853 (galvanic was in figurative use in 1807). Meaning "to coat with metal by means of galvanic electricity" (especially to plate iron with tin, but now typically to plate it with zinc) is from 1839.
He'll swear that in her dancing she cuts all others out,
Though like a Gal that's galvanized, she throws her legs about.
[Thomas Hood, "Love has not Eyes," 1845]
Related: Galvanized; galvanizing.
galvanized (adj.): 1820, "subject to galvanism," past participle adjective from galvanize. As "coated with a metal by galvanism" from 1839, originally in galvanized iron.
Iron covered with zinc has been called galvanised iron, from the fact that we have two metals in different electrical conditions; the zinc, suffering chemical change, oxidising, and acting as a protecting agent to the iron. ["Hunt's Hand-Book to the Official Catalogues," 1851]
galvanometer (n.): instrument for detecting and measuring electric current, 1801, from galvano-, used as a comb. form of galvanism + -meter. Related: Galvanometric. Galvanoscope "instrument for detecting and determining the direction of electric current" is from 1832.
gam (n.): "a leg," 1781, see gams. Called "cant" in the oldest citation.
Gamaliel: masc. proper name, from Greek Gamaliel, from Hebrew Gamli'el, literally "reward of God."
Gambia: West African nation, named for the river through it, which was so called by 14c. Portuguese explorers, said to be a corruption of a native name, Ba-Dimma, meaning "the river." Related: Gambian.
gambit (n.): "chess opening in which a pawn or piece is risked for advantage later," 1650s, gambett, from Italian gambetto, literally "a tripping up" (as a trick in wrestling), from gamba "leg," from Late Latin gamba (see gambol (n.)). Applied to chess openings in Spanish in 1561 by Ruy Lopez, who traced it to the Italian word, but the form in Spanish generally was gambito, which led to French gambit, which has influenced the English spelling of the word. Broader sense of "opening move meant to gain advantage" in English is recorded from 1855.
gamble (v.): "risk something of value on a game of chance," 1726 (implied in gambling), from a dialectal survival of Middle English gammlen, variant of gamenen "to play, jest, be merry," from Old English gamenian "to play, joke, pun," from gamen (see game (n.)), with form as in fumble, etc. Or possibly gamble is from a derivative of gamel "to play games" (1590s), itself likely a frequentative from game. Originally regarded as a slang word. The intrusive -b- may be from confusion with unrelated gambol (v.). Transitive meaning "to squander in gambling" is from 1808. Related: Gambled; gambling.
gamble (n.): "risky venture," 1823, from gamble (v.). As "an act of gambling" by 1879.
gambler (n.): 1738, agent noun from gamble (v.).
gambling (n.): 1784, "habitual indulgence in gambling," verbal noun from gamble (v.). Gambling-house attested by 1794.
gamboge (n.): type of gum-resin from Southeast Asia, used in Europe as a yellow dye and as a purgative in medicine, 1630, in widely varying spellings, from Modern Latin cambogium, ultimately from the source of the place name Cambodia.
gambol (n.): "frolic, merrymaking," 1590s, earlier gambolde "a skipping, a leap or spring" (1510s), from Middle French gambade (15c.), from Late Latin gamba "horse's hock or leg," from Greek kampe "a bending" (on notion of "a joint"), from PIE *kamp- "to bend" (see campus). Ending altered perhaps by confusion with formerly common ending -aud, -ald (as in ribald).
gambol (v.): "skip about in sport," 1580s; earlier gambade (c. 1500), from Middle French gambader, from gambade (see gambol (n.)). Compare Middle English gambon "a ham" (see gammon); English dialectal gammerel "small of the leg;" gamble "a leg." Related: Gamboled; gamboling; gambolling.
gambrel (n.): "hipped roof," 1851, short for gambrel roof (1763), so called for its shape, from gambrel "horse's hind leg" (c. 1600), earlier "wooden bar to hang carcasses" (1540s), perhaps from Old North French gamberel, from gambe "leg," from Late Latin gamba (see gambol).
game (n.): c. 1200, from Old English gamen "joy, fun; game, amusement," common Germanic (cognates: Old Frisian game "joy, glee," Old Norse gaman "game, sport; pleasure, amusement," Old Saxon gaman, Old High German gaman "sport, merriment," Danish gamen, Swedish gamman "merriment"), said to be identical with Gothic gaman "participation, communion," from Proto-Germanic *ga- collective prefix + *mann "person," giving a sense of "people together."

The -en was lost perhaps through being mistaken for a suffix. Meaning "contest for success or superiority played according to rules" is first attested c. 1200 (of athletic contests, chess, backgammon). Especially "the sport of hunting, fishing, hawking, or fowling" (c. 1300), thus "wild animals caught for sport" (c. 1300), which is the game in fair game (see under fair (adj.)), also gamey. Meaning "number of points required to win a game" is from 1830. Game plan is 1941, from U.S. football; game show first attested 1961.
game (adj.1): "lame," 1787, from north Midlands dialect, of unknown origin, perhaps a variant of gammy (tramps' slang) "bad," or from Old North French gambe "leg" (see gambol (n.)).
game (adj.2): "ready for action, unafraid, and up to the task;" probably literally "spirited as a game-cock," 1725, from game-cock "bird bred for fighting" (1670s), from game (n.) in the "sport, amusement" sense. Middle English adjectives gamesome, gamelich meant "joyful, playful, sportive."
game (v.): Middle English gamen "to sport, joke, jest," from Old English gamenian "to play, jest, joke;" see game (n.). The Middle English word is little recorded from c. 1400 and modern use for "to play at games" (1520s) probably is a new formation from the noun; and it might have been re-re-coined late 20c. in reference to computer games. Related: Gamed; gaming.
game-cock: cock bred for fighting or from fighting stock, 1670s, from game (n.) in the sporting and amusement sense + cock (n.1). Figurative use by 1727.
gamekeeper (n.): one who has responsibility for animals kept for sport, 1660s, from game (n.) in the "wild animal caught for sport" sense + keeper.
gamelan (n.): "East Indian orchestra," 1817, from Javanese gamel "to handle."
gamely (adv.): "courageously," 1861, from game (adj.2) + -ly (2). In Old English and Middle English the adverb meant "artfully; joyfully."
gamer (n.): mid-15c., "an athlete" (mid-13c. as a surname, Johannes le Gamer), agent noun from game (v.). Meaning "one devoted to playing video or computer games" is attested by 1981 (by 1975 in reference to players of Dungeons & Dragons). Gamester is attested from 1580s but also sometimes meant "prostitute" (compare old slang The Game "sexual intercourse" (by 1930s), probably from the first game ever played "copulation"). From 1550s as "a gambler." Gamesman is from 1947.
Quite a few of the gamers we've encountered during our monthly strolls down "Arcade Alley" suffer the same chronic frustration: finding enough opponents to slake their thirst for endless hours of play. ["Video" magazine, May 1981]
gamete (n.): "sexual protoplasmic body," 1880, coined 1878 by German cytologist Eduard Strasburger (1844-1912), the widespread attribution of the word's coinage to Mendel being apparently erroneous. From Greek gamete "a wife," gametes "a husband," from gamein "to take to wife, to marry," from PIE root *gem(e)- "to marry" (source also of Greek gambros "son-in-law, father-in-law, brother-in-law;" Sanskrit jamih "brother, sister," jama daughter-in-law;" Avestan zama-tar "son-in-law;" Latin gener "son-in-law"). See also -gamy. The seventh month of the ancient Attic calendar (corresponding to late January and early February) was Gamelion, "Month of Marriages." Related: Gametal.
gamey (adj.): also gamy, 1844, "spirited, plucky," from game (n.) + -y (2). Meaning "tasting or smelling strongly" is from 1863.
gamin (n.): "street urchin," 1837, from French gamin (late 18c.), perhaps from Berrichon dialect gamer "to steal." Introduced in English in translations of Hugo.
Un groupe d'enfants, de ces petits sauvages vanu-pieds qui ont de tout temps battu le pavé de Paris sous le nom éternel de gamins, et qui, lorsque nous étions enfants aussi, nous ont jeté des pierres à tous, le soir, au sortir de classe, parce que nos pantalons n'étaient pas déchirés; etc. [Hugo, "Notre-Dame de Paris"]
gamine (n.): "small, slim, pert young girl," 1899, from French gamine, fem. of gamin.
gaming (n.): c. 1500, "gambling," verbal noun from game (v.). From 1980s in reference to video and computer games. Gaming-house is from 1620s; gaming-table from 1590s.
gamma: third letter of the Greek alphabet, c. 1400, from Greek gamma, from Phoenician gimel, said to mean literally "camel" (see camel) and to be so called for a fancied resemblance of its shape to some part of a camel. Gamma rays (1903) originally were thought to be a third type of radiation, but later were found to be very short X-rays.
gammadion (n.): ornamental figure formed of four capital gammas, Medieval Greek gammadion, diminutive of Greek gamma (see gamma).
gammer (n.): "old woman," 1570s, contraction of grandmother (corresponding to gaffer, but according to OED representing a different construction).
gammon (n.): "ham or haunch of a swine," especially when smoked and cured, early 15c., gambon, from Old North French gambon "ham" (Old French jambon, 13c.), from gambe (Old French jambe) "leg," from Late Latin gamba "leg of an animal" (see gambol (n.)).
gams (n.): "legs," 1781, low slang, probably the same word as gamb "leg of an animal on a coat of arms" (1727) and ultimately from Middle English gamb "leg," which is from French (see gammon). Now, in American English slang, especially with reference to well-formed legs of pretty women, but this was not the original sense.
gamut (n.): 1520s, "low G, lowest note in the medieval musical scale" (the system of notation devised by Guido d'Arezzo), a contraction of Medieval Latin gamma ut, from gamma, the Greek letter, used in medieval music notation to indicate the note below the A which began the classical scale, + ut (now do), the low note on the six-note musical scale that took names from syllables sung to those notes in a Latin sapphic hymn for St. John the Baptist's Day:
Ut queant laxis resonare fibris
Mira gestorum famuli tuorum,
Solve pollutis labiis reatum,
Sancte Iohannes.
The ut being the conjunction "that." Gamut also was used for "range of notes of a voice or instrument" (1630s), also "the whole musical scale," hence the figurative sense of "entire scale or range" of anything, first recorded 1620s. When the modern octave scale was set early 16c., si was added, changed to ti in Britain and U.S. to keep the syllables as different from each other as possible. Ut later was replaced by more sonorous do (n.). See also solmization.